The present invention relates generally to the transmission of diseases. More specifically, the present invention relates to the transmission of spongiform encephalopathy diseases through blood products.
In a variety of therapies, such as transfusions and transplants, body fluids, especially blood components, such as red blood cells, platelets, plasma, and bone marrow, are infused from one or more individuals into a patient. The development of such treatments provide therapies, some of which are life-saving, that cannot otherwise be provided. However, due to the risk of transmission of certain disease states, there may be potential risks with such therapies.
Unfortunately, it is also known that a number of disease states can be transmitted through the infusion of blood products. For example, it is known that blood can carry infectious agents, such as hepatitis virus, human immunodeficiency viruses (an etiological agent for AIDS), cytomegalo virus, Epstein Barr virus, and herpes virus. Much recent effort has been devoted to eliminating the risk of the transmission of hepatitis and acquired immune deficiency syndrome (AIDS) through blood and blood products.
In certain areas of the medical community, recent attention has been focused on transmissible spongiform encephalopathies (TSE). TSE diseases are progressive, lethal central nervous system disorders that are characterized by localized anatomical changes in the brain. These changes consist of vacuoles and protein deposits.
TSE diseases occur in both humans and animals. These neurodegenerative diseases have long latency periods. In humans the latency period can reach up to 30 years. When the disease manifestations finally begin to occur, death usually results within 2 to 4 months; due to the loss of central nervous system function.
TSE diseases can occur: 1) spontaneously; 2) through inheritance; or 3) by iatrogenic exposure to contaminated material. It is believed that the infectious particles responsible for TSE diseases are composed predominantly or perhaps even solely of protein. These proteins have been referred to as prions. It is believed that the infectious prion particles are composed largely, if not entirely, of an abnormal isoform of a normal glycoprotein which is anchored to the external surface of cells. The infectivity of prions has an unconventional property of being unusually resistant to various physio-chemical procedures.
Although TSE diseases have been known for some time, much recent attention has been focused on a new variant of TSE diseases. In March, 1996 Creutzfeldt-Jakob (vCJD) was officially reported. The variant CJD is so called because of the younger ages, than the classical CJD, in which it occurs. Additionally there are also some clinical and pathological differences between the diseases.
There has been some discussion whether there is a link between bovine spongiform encephalopathy ("mad cow disease") and VCJD. Circumstantial evidence suggests exposure to BSE may be the most likely hypothesis for the emergence of vCJD.
Because iatrogenic transmission has been demonstrated with transmissible spongiform encephalopathies including human CJD and vCJD, there may be a question of whether or not such transmissions can occur through blood products. Accordingly, there may be a need for reducing the potential of a risk of the transmission of TSE diseases through blood and/or blood products.